Printing transparent material



PRINTING TRANSPARENT MATERIAL Filed June 24, 1939 INVENTQR. fruugg(fa/104w,

AiITORNEYfi Patented Apr. 1, 1941 PRINTING TRANSPARENT MATERIAL IrvingGurwick, Mount Vernon, Ohio, assignor to Shellmar Products Company,Mount Vernon, Ohio, a corporation of Delaware Application June 24, 1939,Serial No. 280,904

4 Claims.

The present invention relates to an'improved method of printingtransparent materials such as the product known as Cellophane, and hasparticular reference to the use of infra-red rays in the drying ofintaglio inks of the quick-drying type.

A principal object of the invention is the provision of a moresatisfactory method of driving off the solvent of a quick-drying inkafter the ink has been deposited-upon transparent materials.

An additional object of the invention is the provision of a method fordrying or setting intaglio or similar types of inks in which the body ofthe ink is carried in a relatively low boiling solvent, the methodincluding the use of radiant heat imparted by infra-red rays preferablydirected from a source positioned on the side of the transparentmaterial opposite that upon which the ink is deposited.

Still another object of the invention is the drying of intaglio inkdeposits between colors by the combined use of radiant heat originatingfrom a source on the side of the transparent material opposite that uponwhich the ink is deposited and direct heat supplied from rollersrotating in surface contact with the transparent material.

These and other objects will be evident upon the consideration of thefollowing description of a preferred embodiment of the invention and byreference to the drawing. in which the single figure is a diagrammaticview of apparatus constructed in accordance with the invention andadapted to carry out the improved method.

In the printing of transparent materials it has been recognized asdesirable to employ the superimposed relation with respect to eachother.

In such a method, and in fact in any intaglio type of printing, it isdesirable to dry the deposits of ink thoroughly before the next color isreached. this drying operation being necessary to prevent offset orsmearing of the ink. Various types of drying methods have been employedfor setting the inks between colors. The inks generally are of thelacquer type in which the body of the ink is contained in a relativelylow boiling organic solvent.

In the printing of Cellophane it is desirable to run the web through themachine at as fast a speed as possible. Speeds of the order of 200 to600 feet per minute normally are attained in intaglio printing machines.In accordance with the present invention the ink of the consecutivelyapplied colors is dried between color units even at these high speeds bythe use of infra-red lamps which provide radiant. heat, preferably fromthe side of the web opposite that upon which the printing matter isapplied.

As shown in the drawing, an intaglio printing unit is indicateddiagrammatically. The color bath l0 carries a body of intaglio printingink II in which the etched printing cylinder l2 rotates. A conventionaldoctor blade l3 removes excess ink from the printing cylinder before itcomes in contact with the web I of transparent material. An impressioncylinder His-mounted above the etched printing cylinder and'forces theweb against the etched cylinder sufllciently to provide a good printingimpression.

As the web ll passes through the printing unit it has deposited on theunder side thereof a series of designs indicated at IS. The intaglioprinting ink is of the quick-drying lacquer type in which the body ofthe ink may be composed of nitrocellulose and gums, resins and the like,together with the conventional pigments and plasticizers contained in arelatively low boiling organic solvent such as toluol, xylol, andpetroleum products.

After passing through the intaglio printing unit the web is carriedalong on the under side of a series of idler rolls H which are spacedapart as shown in the drawing.

Above the series of idler rolls H is positioned a battery of infra-redray lamps l8, which direct radiant heat upon the unprinted side of thetransparent material. Since the web H is transparent the radiant heatdoes not cause a rise in temperature of the web itself. However, theinfra-red rays pass through the transparent material and contact theunderside of the deposits of ink l6. Since the deposits of ink are-opaque the radiant heat heats the ink and immediately causes thedriving off of the solvent. It is of importance to note that the driving017 of the solvent is from the underside of the ink. This causes the inkto dry from adjacent the Cellophane, and since the drying of the inkadjacent the Cellophane does not prevent the ink from being heated bythe infra-red rays the drying operation proceeds to the'surface of thefreshly deposited ink and causes complete drying without the formationof an outer skin.

It is preferred to employ a series of fans It or any other suitable typeof air transfer mechanism for carrying away the solvent-laden air fromadjacent the underside of the Cellophane.

It will be noted that the rollers I! cover a rather substantial area onthe unprinted side of the Cellophane and shade the Cellophane from theeffects of the radiant heat from lamps l8. In the structure shown thisshading effect does not prevent the Cellophane from being subjected toheat throughout its length of travel because of the heating effect ofthe lamps I8 upon the rollers themselves. That is, although the rollersl1 have no electrical coils they are heated up by the effect of thelamps i8 and being in direct contact with the transparent Cellophaneassist in the drying operation. In this manner there is no dead webspace between the printing unit and the roller 20, about the upper partof which the web finally is passed to the next intaglio printing unit.

It will be seen that this method of operation is most effective inconnection with transparent materials, since these transparent materialsare not themselves heated up by the infra-red rays. The solvent of theink is driven out from the bottom of the deposit and the process is soefllcient that thorough drying is obtained between adjacent colors. Thistype of heat treatment may be em ployed to advantage in the setting ofinks by chemical action. For instance, the radiant heat when applied onthe unprinted side of the web will hasten drying or setting of inks ofthe oxidation or polymerization type.

The various changes which may be made in the arrangement of the apparatuand in the operation of the process without departing from the scope ofthe invention are intended to be included in the appended claims.

I claim:

1. The process of printing, which comprises passing a transparent webthrough a printing operation in which there is deposited on one side ofthe web a lacquer ink having a relatively low boiling solvent, andsubjecting the unprinted side of the web to the action of radiant heatof sufficient intensity to drive oil? said solvent in a relatively shortperiod of time.

2 The process of printing, which comprises depositing an intagliolacquer ink containing a relatively low boiling solvent on one side ofthe web of transparent material, and passing the unprintgd side of theweb adjacent a source of radiant eat.

3. The process of printing a transparent web, which comprises passingsaid web through spaced printing units operative to deposit on said weba quick-drying ink, and subjecting the unprinted side of the web to theaction of radiant heat between said color units.

4. The process of printing a transparent web, which comprises depositinga quick-drying ink on one side of the web, passing the unprinted side ofthe' web in contact with a heated surface, and subjecting the unprintedside of said web to the action of radiant heat.

i IRVING GURWICK.

